FlagSageGuides
Task guides for common cross-border questions, plus the seven flag guides.
Each guide answers one question, lists the official sources, and ends with questions to take to a professional. None of them tells you what to do in your case.
Is there a 183-day rule? What day counts really decide
Why 183 days is not a universal tax rule. How Spain, the UK, New Zealand, the UAE, the US and others count days, plus ties tests and treaties. Research only.
Read the guideDigital nomads and tax residency: why no home does not mean no tax
Why moving often does not remove tax duties. Residence tests, citizenship taxation, work-location rules, social security and employer risk. Research only.
Read the guideLeaving a country: questions to settle before you go
What to settle before you move abroad. Departure dates, split years, ties you keep, exit taxes, deregistration and telling the tax office. Research only.
Read the guideRecords that show where you were and where your life is
Which records show your days and ties across countries, how long the IRS and HMRC say to keep them, and what not to hand to unverified people. Research only.
Read the guideSecond citizenship: what changes and what doesn't
How people get a second citizenship, why dual citizenship rules differ, and which duties such as military service or US tax to check first. Research only.
Read the guideWhen two countries treat you as resident
What happens when two countries both treat you as tax resident. Treaty tie-breakers, residence certificates, mutual agreement and tax credits. Research only.
Read the guideUS citizens living abroad: the duties that follow you
Why US tax duties follow citizens abroad. Filing thresholds, the foreign earned income exclusion, foreign tax credit, FBAR, Form 8938 and renouncing.
Read the guideCitizenship and passports
Descent, naturalization and what a passport does and does not decide.
Flag guideTax residency
How countries decide who they tax, and why 183 days is not the rule.
Flag guideCompany
Where a company is incorporated, managed and owned, and how that links to you.
Flag guideBanking
Account access by residence, CRS and FATCA reporting, and bank checks.
Flag guideAssets
Where assets sit, who owns them, and reporting, pensions and inheritance.
Flag guideLiving base
Visas, residence permits and work rights, kept apart from tax.
Flag guideDigital
Domains, payment accounts, data location and provider restrictions.
Flag guide- Countries covered
- General, with country examples
- Sources
- Each guide lists its sources
- Tax year
- Current rules as checked
- Review
- Not professionally reviewed
Sources checked November 8, 2026